Epidermal Growth Factor Receptor (EGFR) inhibitors, also known as EGFR inhibitors, are new, non-traditional chemotherapy agents that are used to target and destroy “cancer cells”, unlike traditional agents that destroy “healthy cells”, as well as, “cancer cells.”
The use of traditional types of chemotherapy agents are typically associated with toxic side effects. The EGFR inhibitors tend to result in fewer side effects over an area of the body because of the fact that they have a “targeted” characteristic (targeted to select cells).
EGRF Inhibitors and Related Side Effects
Although these non-traditional chemotherapy agents aren’t associated with as many toxic side effects as traditional agents, they are accompanied with some side effects that can influence the patient’s quality of life. Some of these side effects include rash, diarrhea, headaches, infection, changes in hair and nails, inflammatory lung disease, and lab value changes.
EGFR inhibitors are commonly known to cause dry, itchy skin rashes (usually on the face, neck, or chest). These rashes normally occur in a mild to moderate form; however, they can be more serious and cause sores or pustules. In severe skin cases, healthcare practitioners may observe the patient for possible skin inflammation or infection. There are medications that have been shown to successfully treat these rash conditions.
In EGFR-related treatment cases, diarrhea is a common side effect. The severity of diarrhea is graded on a scale of 1 to 4 (1 indicates less severe, 4 indicates more severe). This side effect is normally managed with oral anti-diarrhea medications such as Loperamide (over the counter), Lomotil (prescription), and/or changes in diet.
Changes in hair and nails have been shown in cases of long-term EGFR-related treatment cases. Hair loss or thinning, flaking skin, or lesions may occur on the scalp. Common treatment for these symptoms may be the use of a selenium-based shampoos or oral tetracyclines. Another hair-related symptom may be excessive hair growth (hypertrichosis) of the eyelashes. This condition can eventually irritate or damage the cornea. A known solution to this problem is keeping the eyelashes trimmed.
Infections in the regions of a patient’s fingernails or toenails may also occur in EGFR-related treatment cases. These conditions may cause redness, pus, and pain around the patient’s nail beds. Healthcare practitioners typically treat these conditions with warm soaks, anti-fungals, topical antibiotics, and in extreme cases, nail removal.
Dry skin may occur on the face during short-term use of EGFR-related treatment, or may occur over the entire body in patients under long-term use. Treatments may include creams, lotions, or oral antihistamines to help alleviate accompanying skin itching and flaking.
A more severe, but rare side effect that may accompany EGFR-related agent treatment, is an inflammatory lung disease known as interstitial lung disease (ILD). This disease is inflammation of the interstitium (the tissues that surround and separate tiny air sacs in the lungs) of the lungs.
Accompanying symptoms of this condition include annoying cough, rapid onset of shortness of breath, pneumonitis, or scarring and/or thickening of the lungs. Treatment may include cessation of EGFR-related treatments, using steroid treatments, and in some cases may require hospitalization.
Available EGRF Inhibitors
Some of the available EGFR inhibitors used as “targeted” chemotherapy agents for cancer patients include erlotinib (Tarceva), cetuximab (Erbitux), and panitumumab (Vectibix).
Erlotinib (Tarceva) was approved for use in 2004 as the result of a clinical trial where cancer patients on erlotinib showed a 6.7 month average survival rate versus patients on a placebo that averaged 4.7 months. The EGFR inhibitor later received approval for use in conjunction with gemcitabine chemotherapy for treatment of advanced pancreatic cancer patients. This was the result of a clinical trial that showed better survival rates when erlotinib was used with gemcitabine.
Cetuximab (Erbitux) was approved for use in 2004 in colorectal cancer patients both as a single therapy and also for use in conjunction with irinotecan chemotherapy. Cancer patients in a clinical trial using cetuximab as a single therapy showed a tumor shrinkage rate of 10.8 percent while patients using the combination therapy (both cetuximab and irinotecan chemotherapy) showed a 22.9 percent tumor shrinkage rate. In 2006, cetuximab was approved for use in conjunction with radiation therapy to treat squamous cell carcinoma (for head and neck). Additionally, it was approved to treat metastatic or recurrent squamous cell carcinoma.
Panitumumab (Vectibix) was approved for use in 2006 for cancer patients that showed no success after undergoing multiple other types of chemotherapy and metastatic colorectal cancer patients. The approval of panitumumab was the result of a study where more than 400 cancer patients showed distinct improvement over a period of time. They also showed an 8 percent tumor shrinkage rate.